Electromagnetic switch



April 6, 1965 MASAYOSIHI KAWABATA ETAL 3,

ELECTROMAGNETI C SWI TCH Filed Oct. 23, 1961 3 Sheets-Sheet l fl p; J459434 7a s 15a April 1965 MASAYOSHI KAWABATA ETAL 3,177,331

ELECTROMAGNETIC SWITCH Filed Oct. 25, 1961 3 Sheets-Sheet 2 A ril 6,1965 MASAYOSHI KAWABATA ETAL 3,177,331

ELECTROMAGNETIC SWITCH Filed Oct. 23, 1961 3 Sheets-Sheet 3 F g; 8% a;

United States Patent Claims. (Cl. 200-168) This invention relates toelectromagnetic switches and more particularly to a new and improvedtype of dustproof construction for electromagnetic contactors.

In a conventional electromagnetic switch of the type wherein a coil andstationary iron core are contained within the base structure of theelectromagnetic switch, and the moving iron core and moving contactsupport are contained in a freely slidable manner within a stationarycontact support mounted on the basic structure, the plurality of movingcontacts which are arranged in a row on the moving contact support aredisposed opposite the stationary contacts at recessed window portions onboth sides of the stationary contact support. Consequently, such aconventional electromagnetic switch has had the disadvantage ofaccumulation and adhesion of dust on the contacting members, wherebysatisfactory contacting condition could not be obtained. For thisreason, such electromagnetic switches have heretofore been rendereddustproof by enclosing the entire structure within a housing made oftransparent plastics or steel sheet. Such a measure has beenuneconomical.

It is an object of the present invention to provide a new and simpletype of dustproof construction for electromagnetic switches of thistype.

The manner in which the foregoing objects and other objects of thisinvention may best be achieved will be more clearly apparent byreference to the following detailed description when taken inconjunction with the accompanying illustrations in which the same andequivalent parts are designated by the same reference numerals orletters, and in which:

FIG. 1 is a plan view of one representative embodiment of the presentinvention;

FIG. 2 is a side elevational view of the embodiment shown in FIG. 1;

FIG. 3 is a front elevational view, partly in section, in a directionperpendicular to that of FIG. 2;

FIG. 4 is a plan view of a transparent cover used in the embodimentshown in FIGS. 1, 2, and 3;

FIG. 5 is a plan view showing another embodiment of thepresentinvention; I 1

FIG. 6 is a front elevational view, in section taken along the lineVI-VI of FIG. 5;

FIG. 7 is an exploded, perspective view showing the principal parts ofthe embodiment shown in FIGS. 5

and 6;

FIG. 8 is a plan view showing yet another embodiment of the presentinvention;

FIG. 9 is a side elevational View of the embodiment shown in FIG. 8;

FIG. 10 is an exploded, elevational view of the embodiment shown inFIGS. 8 and 9, showing its state wherein the upper stationary contactassembly and dustproofing structure 1, in which a stationary iron core 2and a coil 3 are enclosed; a lower stationary contact support 4, inwhich a moving iron core 5 and a moving contact support 6 are enclosedin a freely slidable manner; and an upper stationary contact support 7.The foregoing three essential parts are held rigidly together as asingle body by assembly screws 8 and 8a. The upper stationary contactsupport 7 supports upper stationary contacts 9 in a row; and the lowerstationary contact support 4 supports lower stationary contacts 10 alsoin a row. Window portions 11 are provided in aligned disposition on thetwo sides of the said upper and lower stationary contact supports. Theupper and lower stationary contacts 9 and 10 are separated by means ofpartition walls 4a and 7a formed on both sides of the respective contactsupports 4 and '7. Moving contacts 12 are disposed in the said windowportions 11 and are confronted above and below by the stationarycontacts 9 and 10. The window portions 11 on each side are covered andsealed completely by a transparent cover 13 and 13a, which are heldtightly in place by elastic clamp members 15 and 15a having bent ends 16and 16a which fit, respectively, into holes 14 and 14a cut out in thecover 13 and 13a. The transparent covers 13 and 13a are providedrespectively with engaging recesses 13' and 13a at their upper portionsconfronting the partition walls 4a formed on both sides of the lowercontact support 4, and the lower ends of the projections 13" and 13a"defined by the recesses 13 and 13a project to the depthcontacting withthe lower surface of the stationary contact 9. Furthermore, the upperinside portions of the transparent covers 13 and 13a are providedrespectively with vertical slots 13' and 13a confronting the partitionwalls 7a formed on both sides of the upper stationary contact support 7,and the inward directed projections 13" and 13a" formed by the verticalslots 13 and 1311' are attached so as to be in contact with the outsidesurface of the upper stationary contact 10. The elastic clamp members 15and 15a need not be rigidly fixed at their central portions by screws 8and 8a as illus-' trated, but may be anchored in any other "suitablemanner, for example, by fitting said clamp members 15 and 15a intoslots.

As illustrated in FIGS. 1 to 4, since the partition walls of the contactsupports are engaged with the engaging recess 13' and 13a'or verticalslots 13" and 13a of the transparent covers 13 and 13a, rightward andleftward movement of the transparent covers 13 and 13a is avoided.Furthermore, the lower ends of the projections 13" and 13a of thetransparent covers 13 and 13a are in contact with the upper surface ofthe lower stationary contact 9 and the upper projections 13" andllSa aremade so as to be in contact with the outside surface of the upperstationary contact 10, so that the window portions 11 is completelycovered from both sides. Accordingly, even when the electromagneticswitch is mounted in any position entering of airborne dust through theWindow portions is effectively precluded;

The above-described construction has an advantage in that, when theelectromagnetic switch is to be disassembled, or when only the uppercontacting parts are to be disassembled, the transparent covers can beeasily removed by removing the elastic clamp. Furthermore, theabovedescr'ibed construction ailords an electromagnetic switch of simpledustproof form which enables observation, from the outside, of thecondition of the contacting parts.

a,177,ss1

The above-described construction, however, does not provide protectionand partitioning of the terminals on the lower row of terminals. If saidprotection and partitioning were to be provided by terminal partitionwalls formed onthe electromagneticswitch structure, their fabricationwould be difiicult and entails a high cost since they would be requiredto protrude outwardly from the side of the contactor structure. 7

Effective protection'and partitioning of the aforesaid terminals can beprovided in a simple manner by modifying the transparent covers 13 and13a of the above-mentioned embodiment illustrated in FIGS. 1 through 4.The modified covers, which are illustrated in FIGS. 5 through 7 and aredesignated therein by the reference numeral 117, are provided on theiroutside surfaces with partition plates 19, 19, of suitable configurationformed integrally thereon and so disposed'as to be positioned inalignment with the partitions 4a to jointly therewith form upstandingpartitions between the terminals 18, 18, of the lower row when thecovers 17 are assembled in place. The transparent cover 17 is providedwith engaging recess 17' at the upper portion confronting the partithelower surface of the stationary contact 9. Furthermore, the upper insideportion of the transparent cover .37 is provided with vertical slots 17confronting the partition walls 7a formed on both sides of the upperstationary contact support 7, and the inward projection 17' forrned'bythe said vertical slots 17" are attached so as to be incontact with theoutside surfaceuof the upper stationary contact 10%. The covers 17 maybe held in place, for example by elastic clamp members and 15a anchoredby screws 8 and 8a in exactlythe same manner as in the first embodimentillustrated in FIGS. 1 through 4.

Undercertain conditions, the means of holding the dust-proofing coversas described above, that is, such means as elastic clamp members or snapon clamps and screw anchoring, may be disadvantageous because of failureor breakage due to their exposed positions. 7

An embodiment of theinvention wherein the covers are held tightly inposition without the use of such means as elastic clamping members isillustrated in FIGS. 8 through 12. The internal construction of theelectromagnetic switch illustrated inFIGS. 8 through 12 is the same asthat of thetelectromagnetic switch illustrated in FIGS, 1' through 4except the manner of attaching the 1 covers 22 is different.

projection 22' defined by the said recesses 22' projects suficiently tocontact the lower surface of the stationary contact 9' Furthermore, theupper inside portion of the, transparent cover, 22 is provided withvertical slots 22 confronting the partition walls b formed on-both sidesof the upper stationarycontact support7, and the inward projections 22"formed by the vertical slots 22'" of the lower contact support 4, andthe lower end of the are in contact with the outside surface of theupper sta-v tionary contactitl. Briefly stated, coversZZ are clampedEach cover 22 is provided at its two ends with'lugs 23, which are soformed as tofit into corresponding recesses 24 formed in thelowerstationary contact support '0. During assembly of the support B and C,the dustproofing covers 22'are first placed in position'so that theirlugs 23 fit into their respective recesses 24 in the support C; then thesupport B is placed thereon and screwed or otherwise fastened down so asto clamp the covers 22 between itself and the'lower support C.

The above-described construction affords positive and tight retention ofthe covers 22 sons to prevent them from rattling or from slipping offbecause of such effects as impacts and vibrations. Furthermorqthisconstruction affords easy and low-cost fabrication, facility in assemblyand disassembly, and a functional, esthetic design.

While a few particular embodiments of the'present invention have beendescribed, it will'be obvious that many changesv and modifications canbe made in the above de-' scribed details without departing ,from' thenature and spirit of the invention, and it is to be understood that theinvention is not to'be limited to the details'described herein except asset forth in the appended claims.

Whatis claimed is: i V

1. in a dust-proof'switch, a base structure, an upper stationary contactsupport and a lower stationary contact support mounted on said basestructure,van array of upper stationary contacts'and an array. oflowerstationary contacts mounted respectively onsaid upper, and lowersupportspextending along a length of, said switch means on said basestructure mounting movable contacts for electrical connection withrespective ones; of said stationary contacts, electromagnetic meanshoused in said base structure for actuating said movable'contacts,arrays of upper terminals for connection to said upper stationarycontacts and an array of lowerterminals for connection to said lowerstationary contacts disposed along a side'of the switch the improvementwhich comprises dust-proof covers means comprising. said upper supporthaving partitions extending between the upper terminals, said lowersupport having partitions extending between the lower terminals, atransparent cover piecerhaving slots for recerving the partitions onsaidupper support and spaced recesses for receiving the partitions on'saidlower support and extending along-a part of said side of the switchcompletely enclosing and defining a dust-proofspace with said supportsand base structure in jWhlCh said movable and stationary contactsareivisible from externally of the switch for viewing theoperationthereof. 7

2. In a dust-proof switch according to claim 1, including asnap-onresilient clampholding the dust cover-piece in position. v

3. in a dust-proof switch according to claim 2 including at least onescrew holdingtsaid upper support on said base and passing through saidclamp. i

4. he dust-proof switch, a base structure,

support mounted on said base structure, an array of upper stationarycontacts and an array of lower stationary con tacts mounted respectivelyon said upper and lower supports extending along a lengthvof saidswitch, means on switch, the improvement which comprises dustproofcovers meanscornprising said upper supporthaving parti- V tionsextending between-the upper terminals, said lower v supporthaving-partitions between the lower'terrninals, two transparentcover-pieces having slots for receiving the partitions on said uppersupport and spaced. recesses-for receiving the partitions on said lowersupport and err-- 'tendingalonga part of. both said sides of the switchcompletely enclosing-and defining two dust-proof spaces with saidsupports and base structure in which said :movable and stationarycontacts are visible: from externally of the an upper stationarycontact-support and a-lower stationary contact switch for viewing theoperation thereof, and each coverpiece having projections extendinglaterally therefrom and each disposed between each two successive onesof said lower terminals substantially in registry with said partitionson said lower support and each configured to jointly with the lastmentioned partitions define upstanding partitions between said lowerterminals.

5. In a dust-proof switch according to claim 4, includ ing a snap-onresilient clamp clamping both said side cover-pieces and biasing themtoward each other.

References Cited in the file of this patent UNITED STATES PATENTS IrwinJuly 29, 1941 Knapp Dec. 13, 1949 Toth et a1 Dec. 20, 1955 Reichert eta1 Dec. 20, 1955 Droel June 30, 1959 Brunicardi July 21, 1959

1. IN A DUST-PROOF SWITCH, A BASE STRUCTURE, AN UPPER STATIONARY CONTACTSUPPORT AND A LOWER STATIONARY CONTACT SUPPORT MOUNTED ON SAID BASESTRUCTURE, AN ARRAY OF UPPER STATIONARY CONTACTS AND AN ARRAY OF LOWERSTATIONARY CONTACTS MOUNTED RESPECTIVELY ON SAID UPPER AND LOWER SUPPORTEXTENDING ALONG A LENGTH OF SAID SWITCH MEANS ON SAID BASE STRUCTUREMOUNTING MOVABLE CONTACTS FOR ELECTRICAL CONNECTION WITH RESPECT ONES OFSAID STATIONARY CONTACTS, ELECTROMAGNETIC MEANS HOUSED IN SAID BASESTRUCTURE FOR ACTUATING SAID MOVABLE CONTACTS, ARRAYS OF UPPER TERMINALSFOR CONNECTION TO SAID UPPER STATIONARY CONTACTS AND AN ARRAY OF LOWERTERMINALS FOR CONNECTION TO SAID LOWER STATIONARY CONTACTSDISPOSED ALONGA SIDE OF THE SWITCH THE IMPROVEMENT WHICH COMPRISES DUST-PROOF COVERSMEANS COMPRISING SAID UPPER SUPPORT HAVING PARTITIONS EXTENDING BETWEENTHE UPPER TERMINALS THE LOWER SUPPORT HAVING PARTITIONS EXTENDINGBETWEEN THE LOWER TERMINALS, A TRANSPARENT COVER-PIECE HAVING SLOTS FORRECEIVING THE PARTITIONS ON SAID UPPER SUPPORT AND SPACED RECESSES FORRECEIVING THE PARTITIONS ON SAID LOWER SUPPORT AND EXTENDING ALONG APART OF SAID SIDE OF THE SWITCH COMPLETELY ENCLOSING AND DEFINING ADUST-PROOF SPACE WITH SAID SUPPORTS AND BASE STRUCTURE IN WHICH SAIDMOVABLE AND STATIONARY CONTACTS ARE VISIBLE FOR EXTERNALLY OF THE SWITCHFOR VIEWING THE OPERATION THEREOF.